Fix code-review findings (changelog rendering, release skill, sidebar)

- changelog: fix 3 silent RST mis-renders carried over from the old monolith
  — Markdown link in 0.7.0, mismatched/single backticks in 0.18.0 / 0.20.0
- make-release skill contributors one-liner: parallelize the gh fetch, anchor
  the bot filter (was a substring that dropped handles like "abbott"), and join
  with ", " (paste -sd cycles the delimiter -> "@a,@b @c"); finalize now stages
  only the reviewed set (git add -A -- ':!.idea'); drop the obsolete CRLF gotcha
- make_release.py: emit LF not CRLF in the repository.yml insertion (fixes the
  gotcha at the source)
- docs sidebar: drop the hardcoded furo component list; override brand.html to
  include furo's own template + the sponsor button (decoupled from furo
  internals, no upper-bound pin needed); move sponsor styles into custom.css
- .pre-commit-config.yaml: drop stale end-of-file-fixer excludes for the
  deleted contributors/CoC include shims

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

2 files changed, 11 insertions, 8 deletions

diff --git a/docs/_templates/sidebar/brand.html b/docs/_templates/sidebar/brand.html
new file mode 100644
index 000000000..ad0cae989
--- /dev/null
+++ b/docs/_templates/sidebar/brand.html
@@ -0,0 +1,11 @@
+{# Override furo's sidebar brand: keep the original (logo, links home), then add
+   a GitHub Sponsors button just below it. Using "!sidebar/brand.html" includes
+   the theme's own template, so we don't re-list furo's sidebar components and
+   stay decoupled from furo's internal layout. #}
+{% include "!sidebar/brand.html" %}
+<div class="sidebar-sponsor">
+  <iframe src="https://github.com/sponsors/hathach/button"
+          title="Sponsor TinyUSB"
+          height="32" width="114"
+          loading="lazy"></iframe>
+</div>
diff --git a/docs/_templates/sidebar/sponsor.html b/docs/_templates/sidebar/sponsor.html
deleted file mode 100644
index db066a76c..000000000
--- a/docs/_templates/sidebar/sponsor.html
+++ /dev/null
@@ -1,8 +0,0 @@
-{# GitHub Sponsors button, shown just below the logo in the sidebar. #}
-<div class="sidebar-sponsor" style="display: flex; justify-content: center; padding: 0.4rem var(--sidebar-item-spacing-horizontal) 0.6rem;">
-  <iframe src="https://github.com/sponsors/hathach/button"
-          title="Sponsor TinyUSB"
-          height="32" width="114"
-          style="border: 0; border-radius: 6px;"
-          loading="lazy"></iframe>
-</div>